S  B 
939 
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EIMTD 


ENTOMOLOGY  LIB- 


EL    o. 

j: 


NEW    MEXICO 


,e  of 


THE  MECHANIC 


flgricultursl    ExpspimEnt    Slaliim 


BULLETIN  NO.    7.      /r/7^^,    1892 


Scale-Insects  in  New  Mexico 


LAS  ('RUCKS.  N.  M. 

Kro  (JRANDK  RKPTJI'.MC\N 

1892. 


The    Agricultural   Experiment    Station. 


BOARD  OF  CONTROL: 
Board  of  Regents  of  the  College. 


STATION    STAFF.    ' 

Hiram  Hadley,  A.M.,  Director. 

Aiiisworth  E.  Blount,  A.M.,  Horticulturist  and  Agriculturist. 
Elmer  O.    Wooton,  B.S.,  Botanist. 
C.  H.  Tyler  Townseiid,  Entomologist  and  Zoologist, 
Arthur  Goss,  B.S.,  A.C.,  Chemist, 

Harvey  H.   Griffin,  B.S.,  First  Assistant  to  Agriculturist  and 
Horticulturist, 

Watt  Gilmore,  Assistant  in  Meteorology. 


SCALE-INSECTS   IN    NEW    MEXICO. 

By  ('.  H.  Tyler  TowiiHeml. 

The  question  of  scale-insects  is  a  vital  one  to  the  fruit-grower. 
A  considerable  number  of  scales  infest  our  fruit  and  shade  trees,  as 
well  as  our  various  native  ornamental  shrubs  and  plants;  and  in 
view  of  the  recent  recognition  and  quite  rapid  spread  of  the  San 
Jose  scale  in  the  southern  part  of  this  territory,  it  becomes  very 
desirable  that  accounts  of  our  species  be  embodied  in  a  bulletin  for 
the  benefit  of  the  horticultural  public.  The  people  of  southern 
California  years  ago  set  the  example  of  arousing  public  opinion  and 
securing  valid  legislation  for  the  suppression  of  scale-insects  and 
other  pests,  and  it  is  gratifying  to  note  that  we  have  had  in 
this  territory,  for  one  year,  a  similar  law  which  compels  fruit-own- 
ers to  rid  their  orchards  of  all  such  pests.  Being  practically  in 
close  proximity  to  southern  California,  it  is  rather  to  be  wondered 
at  that  we  have  not  more  of  the  fruit  enemies  which  abound 
there,  and  which  may  at  any  time  make  their  appearance  within 
our  limits.  It  is  only  by  the  greatest  vigilance,  and  by  measures  of 
the  utmost  precaution  on.  the  part  of  all  concerned,  that  such  a  con- 
tingency can  be  prevented.  The  action  which  California  has  taken 
in  the  matter  is  commendable,  and  demonstrates  the  entire  practica- 
bility of  proper  legislation  on  this  point.  We  may  well  follow  the 
example  set  us.  and  no  pains  should  be  spared,  nor  any  feasible 
means  neglected,  to  accomplish  the  suppression  of  such  insects  as 
the  Smi  Jose  scale  and  kindred  species. 

CLASSIFICATION    OF    SCALE-INSECTS. 

Iii  order  that  the  fruit-grower  may  be  better  enabled  to  recognize 
the  various  genera  and  species  of  scale-insects,  a  few  paragraphs 
are  devoted  to  their  classification. 


SCALE  INSKCTS 


They  constitute  the  family  known  as  the  Coccidae,  and  belong  to 
the  Homoptera,  which,  is  generally  accepted  by  entomologists  as  a 
division  of  the  order  Hemiptera.  Other  familiar  examples  of  the 
Homoptera  are  the  plant-lice  (Aphididae),  the  seventeen-year  Cicada, 
the  vine  leaf  -hopper,  and  the  tree-hoppers.  The  cochineal  and 
lac  insects  belong  to  the  Coccidae. 

As  there  is  considerable  diversity  of  structure  among  the  species 
of  Coccidae,  this  family  has  been  divided  into  five  sub-families. 
One  of  these,  the  Bfachyscelinae,  includes  species  which  live  in  galls, 
and  are  wholly  confined  to  Australia.  The  four  remaining  sub-fam- 
ilies may  be  ordinarily  distinguished  by  the  following  table: 

1.      Scale  composed  partly   of  .molted  skins,  and  partly  of  a  secre- 
tion of  the  insect 


Scale  composed  of  a  secretion  of  the  insect  alone,  or  else  absent; 
never  in  part  composed  of  molted  skins  ...........  .    '2 

2.  Individuals  usually  fixed  to  plant  on  which  they  live  ;  the  body 

of  the  female  scale-like  or  rather  globular,   with    segmen- 
tation absent  or  indistinct  ................  L<>canhi(t<>. 

Individuals  usually  retaining  the  power  of  motion  ;  the  body  of 
female  usually   distinctly  segmented  ..............    3 

3.  Abdomen  never  terminating  in  two  long  caudal  filaments  .... 

................................  Monophloebinae. 

Abdomen  always  terminating  in  two  long  caudal  filaments  .  . 
.......................................  Cocci  n(  ic. 

Diaspinae.  —  Examples  are  the  various  species  of  Aspidiotus,  to 
which  belong  the  San  Jose  scale,  the  greedy  scale,  and  the  red 
scale  of  the  orange  in  California.  The  genus  Aspidiotus  is  distin- 
guished by  the  female  scale  being  circular,  or  nearly  so,  with  the 
exuviae  either  central  or  more  or  less  marginal  ;  and  the  male  scale 
somewhat  elongated,  with  the  exuvia  more  or  less  central.  The  fe- 
male scale  may  be  distinguished  by  having  two  cast  skins  or  exuviae 
beneath  it,  while  the  scale  of  the  male  has  but  one.  Near  the  cen- 
ter of  the  scale,  or  between  the  center  and  the  margin,  will  be  seen 


IN    NEW    MEXICO. 


a  small  dot  of  a  darker  color  than  the  rest  of  the  scale.  This  marks 
the  location  of  the  cast  skin  or  skins  (exuviae)  lying  beneath  the 
scale,  and  its  position  serves  as  a  character  for  distinguishing  differ- 
ent species  and  even  genera  of  this  sub-family. 

Lecaninae. — Examples  are  the  various  species  of  Lecanium,  to 
which  belong  the  black  scale  of  California;  the  cottony  maple- 
scale  (Pnlvinaria  innumerabilis  Rathv. ) ;  and  the  lac  insect  (Carter ia 
lacca  Ker. ).  In  the  genus  Lecanium  the  female  lays  her  eggs  be- 
neath the  scale,  and  secretes  no  cottony  material.  In  the  genus 
Pulvinaria  the  female  secretes  a  mass  of  cottony  material,  in  which 
the  eggs  are  deposited. 

Monophloebinae.—  Examples  are  the  various  species  of  Icerya,  to 
which  belongs  the  famous  fluted  scale,  so  destructive  to  the  orange 
in  California  and  originally  brought  from  Australia ;  also  the  mes- 
quite  scale  mentioned  in  this  bulletin,  and  which  will  probably  form 
a  new  genus.  There  are  some  gigantic  species  of  this  sub-family  in 
Australia,  some  of  them  reaching,  the  length  of  nearly  two  inches ! 

Coccinae. — Examples  are  the  cochineal  insect  (Coccus  cadi  L.); 
and  the  mealy  bugs  (Daotylopiu8\. 

GENERAL    HABITS    OF    SCALE-INSECTS. 

The  female  scale-insect  is  always  wingless,  and  does  not  undergo 
a  complete  metamorphosis.  She  fixes  her  beak  in  the  bark,  stem, 
leaf,  or  fruit  while  young,  and  becomes  stationary  (except  the  Mon- 
ophlochlnac  and  Coccinae),  excreting  and  forming  her  scale  as  she 
grows. 

The  male,  however,  of  all  scale-insects  undergoes  a  complete 
metamorphosis,  and  is  furnished  in  the  adult  state  with  a  single  pair 
of  wings.  The  hind  pair  is  wanting,  but  is  represented  by  a  pair  of 
club-like  appendages  called  halteres  or  balancers.  Each  of  these 
appendages  is  furnished  with  a  hooked  bristle,  which  fits  into  a 
pocket  on  the  margin  of  the  wing  of  the  same  side,  and  doubtless 
serves  to  brace  and  strengthen  the  flight.  The  adult  male  has  no 
organs  for  obtaining  food,  and  takes  no  nourishment,  his  sole 


SCALE-INSECTS 


object  in  life  being  to  impregnate  the  female,  which  is  soon  accom- 
plished. The  mouth  parts  are  lost  during  the  metamorphosis,  and 
what  is  strange  enough,  their  place  is  supplied  by  a  second  pair  of 
eyes ! 

As  soon  as  the  female  scale-insect  is  fertilized,  her  body  increases 
in  size  and  becomes  distended  with  eggs.  These  are  deposited 
either  beneath  the  scale,  the  body  of  the  female  meantime  shrivel- 
ing until  it  remains  but  a  shrunken  skin  beside  the  mass  of  eggs ; 
or  a  cottony  sac  is  excreted  by  the  female  posteriorly  to  contain  the 
eggs,  and  in  which  they  hatch. 

When  the  young  insects  hatch,  they  may  be  seen  with  a  lens 
crawling  over  the  surface  of  the  bark  or  leaf,  preparatory  to  set- 
tling down  and  fixing  their  beaks  therein  (except  the  two  sub-fam- 
ilies above  mentioned,  which  do  not  become  stationary).  At  this 
time,  their  bodies  are  very  tender,  but  shortly  after  fixing  themselves 
they  begin  to  exude  a  scaly  covering  to  serve  as  a  protection  to 
themselves. 

Scale-insects  can  spread  from  one  orchard  to  another  by  the  female 
crawling,  or  being  carried  by  birds  or  the  wind.  She  may  even  be 
carried  by  attaching  herself  to  bees,  and  other  insects.  The  larger 
species  of  scales  more  frequently  spread  by  crawling ;  but  the  smaller 
ones,  such  as  the  species  of  Aspidiotus,  are  no  doubt  often  spread  by 
the  other  means  referred  to. 

NO.   i.     THE  SAN  JOSE  SCALE  (Aspidio1n-x  pemiriosus  Conistock). 

Plate  I.  fig.  1. 

Scale  of  Female. — The  female  scale  is  flat  and  circular,  with  the 
exuviae  central  or  nearly  so.  It  is  grayish  in  color,  except  the  ex- 
uvial  spot  which  varies  from  yellowish  to  blackish.  In  some  spec- 
imens, according-  to  Comstock,  the  outer  part  of  the  scale  is  marked 
with  radiating  ridges.  Diameter,  2  mm.  (.08  inch). 

Female. — Body  yellowish  and  nearly  circular  in  outline,  segmen- 
tation distinct.  The  last  segment  presents  the  following  characters : 
Only  two  pairs  of  lobes  visible,  first  pair  converging  at  tip,  notched 


IN    NEW   MEXICO. 


about  midway  their  length  on  lateral  margin,  and  often  bearing  a 
slight  second  marginal  notch  near  tip.  Second  pair  notched  once 
on  lateral  margin. 

Scale  of  Male. — Smaller,  quite  different  in  appearance,  being 
somewhat  elongated  instead  of  circular,  blackish  in  color,  and  with 
the  exuvia  between  the  center  and  the  anterior  margin. 

^99' — According  to  Comstock,the  eggs  are  white ;  but  according 
to  my  own  observation,  they  turn  to  an  orange-yellow  color  in  the 
spring.  They  hatch  here  about  the  first  or  second  week  in  May. 

Food-plants.  —Found  here  on  apple,  pear,  plum,  peach,  quince, 
and  rose.  Attacks  bark,  leaves,  and  fruit.  It  has  not  yet  occurred 
here  on  the  apricot,  but  has  been  reported  on  this  fruit  in  Califor- 
nia. It  also  infests  the  cherry;  in  fact,  all  the  deciduous  fruits 
are  liable  to  its  attacks. 

-  This  species  is  also  known  as  the  pernicious  scale,  and  has  been 
brought  into  New  Mexico  on  young  trees  from  California.  It  was 
first  noticed  as  injurious  in  San  Jose,  whence  the  popular  name.  In 
California,  it  has  proven  to  be  the  most  destructive  scale  known  on 
deciduous  fruits,  and  also  the  most  difficult  to  kill.  It  spreads 
rapidly. 

A  reliable  characteristic  by  which  this  scale  may  be  recognized, 
when  numerous,  consists  in  the  red  discoloration  of  the  bark  occa- 
sioned by  its  attacks.  The  discoloration  appears  in  reddish  blotches 
over  the  bark,  and  when  the  latter  is  badly  infested,  extends  through 
the  bark  and  into  the  sapwood.  It  seems  that  the  weather  during 
the  past  winter  has  had  some  effect  on  the  scales,  many  of  them  ap- 
pearing winter-killed. 

Parasites. — Three  species  of  minute  hymenopterous  parasites  of 
this  scale  are  known  in  California.  They  are : 

Aphelinus  myUlaspidis  Le  Baron  (Plate  I,  fig.  4) :  This  is  a  little 
four- winged  fly,  the  female  of  which  is  about  0.64  of  a  millimeter  in 
length,  with  a  wing  expanse  of  1.28  mm.  Its  general  color  is  bright 
lemon-yellow;  the  base  of  the  antennae  or  feelers  is  more  or  less  dusky, 
the  eyes  blackish,  the  ocelli  or  simple  eyes  carmine,  mandibles  or 


SCALE-INSECTS 


jaws  brown,  and  legs  and  wing- veins  bright  yellow.  The  wings  are 
delicate  and  hyaline,  but  sometimes  with  a  pale  yellowish  shade. 
The  males  average  slightly  smaller  in  size,  and  the  club  of  anten- 
nae is  a  little  more  truncate  at  tip.  With  these  exceptions  they  can 
hardly  be  distinguished  from  the  female.  (Drawn  from  Howard's 
description.) 

This  species  has  been  found  parasitic  on  Mytilaspis  pomorum 
(in  111.,  Mo.,  N.  Y.  ?,  Calif.) ;  Chionaspis  pinifoliae  (in  Mo.  ?,  B.C.); 
Mytilaspis  sp.  on  linden  (D.  C.) ;  Diaspis  carueli  on  juniper  (D.C.); 
and  Aspidiotus  p&rniciosus.  It  was  bred  from  the  last  scale  by  Mr. 
E.  M.  Ehrhorn,  of  California  (see  Insect  Life,  vol.  iii,  p.  487). 

In  order  to  show  the  efficiency  of  this  parasite,  Mr  Howard  has 
compiled  the  following  table  from  Dr.  Le  Baron's  tables,  showing 
that  it  alone  destroyed  more  than  63  per  cent,  of  the  whole  number 
of  scales.  . 

Whole    number    of   scales   collected   from   apple    in   different 

gardens 844 

Number  with  round  holes    through    which   this    parasite    had 

escaped 289 

Number  having  larvae  of  this  parasite  under  them ....    244 

Number  destroyed  by  mites  or  unknown  cause 254 

Number  of  healthy  and  sound  scales 57 


Whole  number 844 

Aphelinus  fusdpennis  Howard :  This  is  a  very  much  smaller  par- 
asite, only  0.06  of  a  millimeter  in  length,  and  with  a  wing  expanse  of 
1.3  mm.  Its  general  color  is  dull  honey-yellow ;  the  antennae  are 
smoky,  blackish  at  tip ;  eyes  blackish,  ocelli  dark  crimson ;  a  distinct 
transverse  black  band  on  occiput  behind  eyes,  scutellum  somewhat 
blackish  at  tip,  abdomen  with  five  dusky  transverse  lateral  bands, 
legs  and  wing-veins  honey-yellow.  Front  wings  with  an  indefinite 
smoky  patch  below  the  stigma  (spot  near  front  border  of  wing),  and 
another  darker  crescent-shaped  streak  near  base  of  wing,  convex  on 


inside.  (Drawn  from  Howard's  description.)  The  male  was  un- 
known to  Mr.  Howard. 

This  species  is  also  widespread  and  quite  a  general  feeder.  It  has 
been  bred  from  Axpidiofus  pcrnlclos/is  (Cal.);  Chionaspis  euontjnn 
(Ma.);  MyHlaspi*  </lorerii  on  orange  (D.C.) ;  and  Mytilaspib pomorum 
(Gal.).  Mr.  E.  M.  Ehrhorn  suspects  that  it  is  also  parasitic  on  the 
greedy  scale  (Aspidwhis  rapcu-).  See  Insect  Life,  vol.  iii,  p.  487. 

Coccaphagus  cih'iiui*  Craw  MS.:  This  parasite  has  appar- 
ently never  been  described.  It  is  0.03  of  an  inch  in  length.  Ke- 
garding  the  value  of  this  species  as  a  parasite,  the  following  letter 
from  Mr.  D.  W.  Coquillett,  published  in  the  "California  Fruit 
Grower,"  Sept.  1889,  is  quoted: 

Concerning  the  parasite  of  the  red  scale  in  the  San  Gabriel  Valley,  Acting 
Entomologist  Howard  writes  me  that  it  is  probably  a  new  species  belonging  to 
the  genus  Coccophagus.  It  is  a  minute  four-winged  fly  scarcely  as  large  as  the 
head  <>f  a  small  pin;  its  eggs  are  laid  singly  in  or  upon  the  scales,  and  the  larva 
or  grub  that  hatches  from  this  egg  feeds  upon  the  scale  insect,  and  after  com- 
pleting its  growth  arid  passing  through  its  preparatory  stage,  it  gnaws  a  round  hole 
through  the  scale  and  thus  makes  its  escape.  This  parasite  occurs  in  nearly  all  of 
the  orange  groves  in  the  San  Gabriel  Valley,  and  in  some  of  them  its  work  is  very 
noticeable.  This  is  especially  the  case  in  the  large.  Chapman  groves,  in  which  I  de- 
tected this  parasite  two  years  ago.  During  a  visit  to  this  grove  a  few  days  ago 
it  was  almost  impossible  to  find  any  young  red  scales  on  the  infested  trees,  while 
in  other  localities  where  this  parasite  does  not  occur,  almost  every  leaf  contains 
one  or  more  of  the  young  scales,  this  being  the  season  of  the  year  when  they  are 
most  abundant.  Mr.  A.  B.  Chapman  informs  me  that  there  is  less  red  scale  on 
his  fruit  this  year  than  there  has  been  since  first  his  trees  became  so  seriously  in- 
fested with  these  pests.  I  have  taken  the  necessary  steps  for  introducing  this  par- 
asite into  a  locality  where  it  did  not  previously  exist,  but  it  will  be  several  months 
yet  before  the  result  of  this  experiment  can  be  determined. 

This  parasite  destroys  the  red  scale  of  the  orange  (Aspldiotus 
auranfii),  and  its  yellow  variety  (A.  citrinus)  in  California;  and 
Mr.  E.  M.  Ehrhorn  has  also  bred  it  in  California  from  the  San 
Jose  Scale  (A.  perniciosus).  See  Insect  Life,  vol.  iii,  p.  487. 

NO.  n.     THE  WHITE  PEAR  SCALE    (Aspidiotus  rapax   Comstock). 

Plate  I,  fig.  2. 

Scale  of  Female. — Very  convex;  exuviae  between  center  and  one 
side,  and  covered  with  secretion.  Scale  is  gray,  somewhat  trans- 


10  SCALE-INSECTS 


parent  so  that  it  appears  yellowish  when  covering  a  living  female; 
prominence  covering  exuviae  is  dark  brown  or  black,  usually  with  a 
central  dot  and  concentric  ring  which  are  white.  Ventral  scale  snowy 
white,  usually  entire.  Diameter  1.5  mm.  (0.06  inch). 

Female. — Body  nearly  circular  in  outline,  bright  yellow  in 
color  with  more  or  less  translucent  blotches.  The  last  segment 
presents  the  following  characters:  Groups  of  spinnerets  wanting. 
Only  one  pair  of  well-developed  lobes,  the  median,  present.  These 
are  prominent,  and  each  one  is  furnished  with  a  notch  on  each  side. 
Second  and  third  pairs  of  lobes  represented  by  minute  pointed  pro- 
jections of  margin  of  body. 

Egg. — The  eggs  and  newly  hatched  larvae  are  yellow.  (From 
Comstock's  description.) 

Food-plants. — This  scale  attacks  a  great  number  of  plants, 
trees  and  shrubs.  In  California  it  has  been  found  on  olive,  moun- 
tain laurel  ( Umbellularia  californica),  almond,  quince,  fig,  willow, 
eucalyptus,  acacia,  apple,  pear,  and  others.  In  Florida,  on  Euony- 
mus  japonicus.  It  has  been  found  here  on  apple,  pear,  and  peach. 
Like  the  preceding  scale,  it  affects  not  only  the  bark  of  the  trunk 
and  limbs  but  the  leaves  and  fruit  as  well. 

This  species  is  also  known  as  the  greedy  scale.  It  sometimes 
occurs  in  a  locality  in  great  numbers,  when  it  becomes  very  destruct- 
ive, but  as  a  rule  it  does  not  spread  rapidly  and  is  not  to  be  com- 
pared with  the  San  Jose  scale.  If,  however,  it  is  allowed  to  gain 
a  good  foothold,  it  will  be  troublesome  to  exterminate  it,  owing 
to  the  large  number  of  plants  upon  which  it  subsists. 

Parasites. — Aphelinus  fuscipennis  Howard,  mentioned  under 
San  Jose  scale,  is  suspected  by  Mr.  E.  M.  Ehrhorn  of  being  a 
parasite  of  this  species  also.  (See  Insect  Life,  vol.  iii,  p.  487.) 

NO.  in.     THE  CONVEX  SCALE  (Aspidiotus  coiii'cxus  Comstock). 

Plate  I,  fig.  3. 

This  species  very  closely  resembles  A.  rapcur.  in  the  shape  and 
color  of  its  scale.  It  is  only  by  a  careful  study  and  comparison  of 
the  two  forms  that  it  can  be  distinguished.  A  careful  examination 


IN    NEW    MEXICO.  11 


of  their  structure  shows  them  to  be  specifically  distinct.  This 
species  may  be  distinguished  from  A.  rapax  by  the  following  char- 
acters of  the  last  abdominal  segment  of  the  female :  Four  groups 
of  spinnerets  (none  in  A.  rapax)',  the  superior  lateral  groups  con- 
sist of  about  seven,  and  the  inferior  lateral  groups  of  about  four 
spinnerets. 

Food-plants. — Very  common  in  California  on  the  bark  of  the 
trunk  and  limbs  of  the  native  willows.  It  has  been  found  in  great 
numbers  here  on  the  bark  of  trunk  and  branches  of  our  native 
cottoiiwood  (Populus  fremontii).  The  bark  of  the  trunk  of  one 
tree  was  entirely  covered.  It  has  also  been  found  here  in  great  num- 
bers on  the  limbs  and  twigs  of  an  ash  (Fraxinus  sp/). 

Parasites. — Great  numbers  of  the  scales  on  cottonwood  showed 
minute  holes  from  which  some  hymeiiopterous  parasite  had  emerged. 
There  were  no  living  insects  under  such  scales,  showing  that  the 
parasite  had  done  much  good  work  in  keeping  the  scales  in  check. 
Those  on  ash  were  also  well  parasitized. 

NO.  iv.     CHILOPSIS  SCALE   ( Aspidiotus  n.  sp.  ?). 

This  species  bears  some  resemblance  to  Aspidiotus  nerii 
Bouche,  but  is  probably  a  new  species.  Professor  Comstock,  after  an 
examination  of  specimens,  writes  that  it  is  an  Aspidiotus  unknown 
to  him,  and  probably  undescribed.  Further  material  is  necessary 
before  a  description  can  be  drawn  up,  therefore  nothing  more  than 
a  mere  notice  of  its  occurrence  is  given  here.  -__  . 

Food-plants. — This  species  was  found  plentifully  infesting  the 
leaves,  mostly  on  the  upper  side,  of  a  bush  of  Chilopsis  saligna  in 
the  yard  of  Hon.  A.  L.  Christy,  of  Las  Cruces,  who  first  called  my 
attention  to  this  scale.  At  date  of  examination,  August  25,  1891, 
the  scales  were  nearly  all  very  small,  and  some  orange-yellow  young 
were  seen  outside.  There  were  a  few  larger  scales,  containing  eggs 
beneath  them.  The  scales  seemed  to  be  confined  to  the  leaves. 

NO.  v.     THE  LOCUST  SCALE  (Lecanium  robiniae  Riley  MS.). 
This  is  an  entirely  different  scale,  in  appearance  and  size,  from 
all  of  the  preceding  species,  which  belong  to  the  genus  Aspidiotus. 


12  SCALE-INSECTS 


It  is  a  brown,  or  reddish-brown  scale,  hemispherical  in  form,  hard 
in  texture,  and  varies  from  3  to  5  mm.  in  breadth  and  4  to  (> 
mm.  in  length.  Some  of  them  are  very  dark  brown  in  color.  Be- 
neath this  scale,  as  in  the  preceding  species,  is  to  be  found  either  the 
soft  insect  or  the  eggs.  The  species  has  not  been  described,  and  I 
will  not  attempt  to  give  other  than  the  above  brief  description  here. 
Professor  Riley,  who  has  seen  specimens,  has  furnished  the  above 
manuscript  name  to  be  used  in  referring  to  the  species.  The  short 
description  and  the  food-plant  will  doubtless  enable  its  recognition. 

Egg. — The  eggs  are  pale  reddish-pink  in  color,  very  small, 
and  a  great  many  are  to  be  found  under  one  scale.  They  were  ob- 
served to  be  hatching  May  22. 

Food-plants. — This  scale  has  been  found  here  only  on  im- 
ported trees  of  black  locust  (Rob  In  id  jwinldcdcid),  the  branches 
and  twigs  of  which  it  very  plentifully  infests.  It  is  more  or  less 
unnoticeable  on  account  of  its  color  being  much  the  same  as  that 
of  the  twigs  upon  which  it  occurs. 

Parasites. — No  true  parasites  have  been  observed.  A  locust 
tree  which  was  infested  with  the  scale  was  found  to  be  well  stocked 
with  the  California  Cooclnella  oculata,  and  its  ashy  gray  variety 
(C.  abdominalis).  These  undoubtedly  prey  upon  this  and  other 
scales.  The  variety  seemed  to  predominate,  and  though  all  stages 
from  eggs  to  adults  were  to  be  found  May  22,  the  pupae  were  by 
far  the  most  abundant. 


NO.   VI. 


SOFT  PEACH   SCALE   (LcCfllUHIK  Sp.). 


A  single  specimen  of  a  soft,  brownish,  more  or  less  hemispher- 
ical scale-insect,  about  5  mm.  in  length,  was  found  April  11,  011  a 
branch  of  the  peach.  No  others  were  found,  and  it  is  simply  men- 
tioned here  so  it  may  be  looked  for  by  fruit-growers.  We  shall 
be  glad  to  receive  any  specimens  of  it  that  may  be  found.  Unlike 
all  the  preceding  species,  it  is  simply  the  bare,  soft  insect  that  must 
be  looked  for,  as  it  apparently  does  not  cover  itself  with  a  scale. 


IN    NEW    MEXICO.  13 


NO.  vii.     THE  YUCCA  SCALE  (LecanocUaspis  yuccae  Kiley  MS.). 

This  is  a  round,  hemispherical,  whitish  scale,  about  3  to  4  mm. 
in  diameter,  and  of  hard  texture.  The  scale  bears  a  median  longi- 
tudinal carina  or  keel  above,  and  is  a  little  narrower  than  long. 
This  species  is  also  undescribed,  and  the  above  manuscript  name 
was  furnished  by  Professor  Riley.  It  can  be  easily  recognized 
when  seen. 

Egg. — The  eggs  under  dried  scales  are  pale  yellowish  or 
whitish,  and  a  considerable  number  occur  under  one  scale. 

Food-plants, — This  scale  was  found  on  leaves  of  DasyUrion 
tvheeleri,  March  14,  1891,  in  the  Organ  mountains.  It  was  later 
found  on  the  large-leaved  yuccas  (probably  Yucca  macrocarpa),  in 
the  same  mountains.  In  both  plants,  it  infests  the  upper  side  of 
the  leaves  very  plentifully,  chiefly  at  and  near  their  bases.  These 
plants  are  highly  ornamental,  and  the  yuccas  especially  may  be 
used  to  advantage  on  lawns.  Therefore  this  scale  becomes  of  con- 
siderable importance  from  an  economic  standpoint. 

Parasites. — Some  of  the  scales  which  have  been  collected  were 
found  infested  with  a  hymenopterous  parasite,  the  black  perfect  in- 
sect of  which  could  be  seen  inside  the  scale  through  a  small  round 
hole  where  it  was  about  to  emerge. 

NO.  vin.     THE  LARREA  SCALE  (Signoretia  sp.  ?  ). 

This  scale  is  enclosed  in  a  white  felted  or  cottony  covering.  The 
insect  itself  is  of  a  light  reddish-brown,  with  the  legs  and  antennae 
concolorous.  The  adult  female  has  apparently  8  joints  in  the  anten- 
nae, and  the  legs  are  present.  The  first  antennal  joint  is  short.  The 
larva  has  only  six  antennal  joints.  The  dimensions  are  as  follows: 
Length  of  adult  female,  about  4  mm  ;  width,  2  mm.  Length  of 
felted  sac,  5  to  6  mm;  width,  2  to  2.5  mm. 

Egg.— The  eggs  are  whitish  in  color  and  are  enclosed  in  the 
end  of  the  felted  sac,  behind  the  body  of  the  female,  the  head  of  the 
female  being  usually  more  or  less  thrust  through  the  anterior  end  of 
the  sac. 


14  SCALE-INSECTS 


Food-plants. — Found  abundantly,  May  13,  on  leaves  of  the 
creosote  bush  (Larrea  mexicana) ;  occasionally  on  the  stems  also. 
It  is  usually  on  the  underside  of  the  leaf,  which  is  small  and  very 
nearly  covered  by  the  felted  sac.  Young  specimens  were  also  found 
this  date,  which  were  beginning  to  exude  a  sac,  though  the  eggs 
found  in  the  sacs  of  adult  females  were  unhatched.  It  was  ob- 
served that  the  whitish  sacs  were  likely  to  escape  notice  among 
the  young  fruit  of  the  Larrea,  which  was  just  setting  and  was  cov- 
ered with  a  whitish,  woolly  pubescence. 

NO.  ix.     PALMER'S  ICERYA  (leery a  palmer  i  Riley  and  Howard  ). 

Plate    II,    figs.    1    and    2. 

This  scale  does  not,  so  far  as  the  writer  is  aware,  occur  in  New 
Mexico.  As  will  be  seen,  however,  it  becomes  very  desir- 
able to  treat  it  here,  since  it  is  not  unlikely  that  it  may  some 
day  reach  us.  The  adult  stages  are  as  yet  unknown  to  science,  and 
consequently  can  not  be  described.  A  description  of  the  first  and 
second  larval  stages  will  be  found  in  Insect  Life,  vol.  iii,  pp.  104-5, 
but  is  too  technical  to  be  inserted  here.  The  larvae  are  apparently 
reddish-yellow  in  color,  but  their  cast  skins  are  white. 

Food-plants. — This  species  was  found  by  Dr.  Edward  Palmer 
July  30,  1887,  on  the  Muscat  of  Alexandria  grape,  at  San  Jose  de 
Guaymas,  nine  miles  north  of  Guaymas  proper,  in  Sonora,  Mexico. 
The  specimens  found  were  only  the  younger  stages,  and  were  fixed 
alon^the  main  ribs  of  the  leaf,  principally  on  the  under  side.  This 
would  prove  a  new  and  most  undesirable  pest  to  our  Muscat  grapes 
if  introduced  here,  and  with  the  Santa  Fe  K.  R.  connections  be- 
tween Guaymas  and  this  territory  it  is  by  no  means  an  impossibil- 
ity. All  vines  brought  from  Old  Mexico  should  be  most  thoroughly 
overhauled  before  they  are  allowed  to  enter  American  territory. 

Parasites. — It  is  reported  in  Insect  Life,  1.  c.,  that  the  pupa- 
rium  of  a  dipterous  parasite,  apparently  of  the  family  Phoridae, 
was  plainly  to  be  seen  within  one  of  the  mounted  larvae  of  the 
second  stage. 


IN   NEW  MEXICO.  15 


NO.   X.        COTTONY  MESQUITE  SCALE  (n.  gen.  et    n.  Sp.). 

This  is  a  large,  soft  scale,  red  or  brick-red  in  color,  and  bear- 
ing a  snow-white,  more  or  less  distinctly  fluted,  cotton-like,  but 
compact  egg-sac,  which  is  attached  to  the  postero- ventral  portion  of 
the  insect,  and  is  cylindrical  in  general  form.  The  insect  is  en- 
tirely red,  except  the  legs,  antennae  and  proboscis,  which  are 
black ;  and  the  egg-sac,  which  is  white.  Pinned  specimens  usually 
become  reddish-yellow  in  color,  while  alcoholic  specimens  acquire  a 
reddish-brown  color.  This  scale  also  exudes,  particularly  around 
the  edge  of  its  body,  a  certain  number  of  curled  white  cottony  fila- 
ments, in  addition  to  the  egg-sac.  The  dimensions  of  the  larger  spec- 
imens collected  in  July,  1891,  and  May,  1892,  are  as  follows:  Length 
of  body,  5  to  7  mm. ;  anterior  width  of  body,  2  to  3  mm. ;  posterior 
width  4  to  5  mm.  Length  of  egg-case,  5  to  6  mm. ;  width,  about 
4  mm.  Specimens  collected  June  8,  1892,  measure  12  to  13  mm.  in 
length,  including  egg-sac;  sac  measures  10  mm. 

This  scale  will  probably  form  a  new  genus,  according  to  Profes- 
sor Kiley  who  has  examined  specimens.  It  is  nearly  related  to  the 
Icerya  of  California,  though  somewhat  more  removed  from  it 
than  the  preceding  species,  which  is  a  member  of  the  same  genus. 

Egg. — In  color  the  eggs  are  orange-red.  They  were  just  be- 
ginning to  hatch  within  the  sacs,  June  8. 

Food-plants. — Found  on  twigs  and  branches  of  mesquite 
(Prosopis  juliflora)  rather  plentifully,  July  28,  1891,  many  of  them 
being  at  this  time  small.  Found  more  sparingly,  but  in  larger 
specimens,  May  13  to  18,  1892;  though  two  or  three  smaller  ones 
without  egg-sacs  were  also  seen.  A  good  number  of  large  specimens 
were  found  June  8.  This  scale,  it  is  possible,  may  some  day  take 
to  certain  cultivated  plants,  in  which  case  it  will  prove  a  serious 
enemy. 

Parasites. — No  true  parasites  have  been  found,  but  the  two 
species  of  lady-birds,  previously  mentioned,  frequented  the  mesquite 
branches  where  the  scales  were  found,  and  doubtless  prey  upon  them. 
In  the  same  connection,  it  may  be  mentioned  that  two  species  of 


16  SCALE-INSECTS 


ants,  one  of  moderate  size  and  the  other  very  small,  were  seen  at- 
tending these  scale-insects,  from  which  they  obtain  a  honey-like  ex- 
udation. The  ants  rather  serve  to  protect  the  scales  by  warding  off 
parasites  and  predaceous  insects.  This  scale-insect  was  noticed  to 
exude  a  drop  of  a  clear  honey-like  fluid  from  the  back  posteriorly, 
upon  which  the  ants  fed. 

PARASITES  AND  OTHER  ENEMIES  OF  SCALE-INSECTS. 

The  insect  enemies  of  scale-insects  may  be  divided  into  two  cate- 
gories :  True  parasites,  which  live  internally  in  the  host  insect,  and 
predaceous  insects,  which  attack  the  scales  externally  and  devour 
them  bodily. 

The  true  parasites  are  very  small  members  of  the  orders  Hy- 
menoptera  and  Diptera,  more  particularly  the  former  in  the  case  of 
scale  parasites.  The  hymenopterous  parasites  belong  principally 
to  the  families  Chalcididae  and  Prodofrupidae,  two  or  three  spe- 
cies of  which  have  been  more  or  less  briefly  described  in  the  pre- 
ceding pages.  The  dipterous  parasites  belong  principally  to  the 
Ochthiphilidae,  a  family  of  acalyptrate  Muscidae,  and  perhaps  to 
some  other  families  of  the  same  division.  These  parasites  deposit 
their  eggs  in  or  upon  the  scale-insects,  and  the  newly-hatched  para- 
site lives  within  the  body  of  its  host  until  full  grown,  when  it  trans- 
forms and  issues  as  a  perfect  insect. 

The  chief  predaceous  insects,  which  are  useful  in  destroying 
scales,  are  the  following:  Coccinellidae,  or  lady-birds;  and  certain 
predaceous  lepidopterous  larvae,  belonging  to  the  families  Noc- 
iuidae,  Phyvitidae,  Tineidae,  and  Pyralidac.  The  predaceous  ene- 
mies have  proven  of  more  value  in  California  than  the  true  para- 
sites, 

Of  the  Coccinellidae,  or  lady -birds,  we  have  here  two  very  efficient 
forms,  which  are  mentioned  in  the  preceding  pages.  They  are 
Coccinella  oculafa,  and  its  ashy-gray  variety  ( C.  abdomincdis,  which 
looks  like  an  entirely  different  species.  The  former  is  black  with 
a  yellow  spot  on  each  wing-cover,  and  the  head  and  forward  margin 
of  thorax  whitish.  The  variety  is  entirely  creamy -jjray,  with  eight 


IN    NEW    MKXLCO.  17 


spots  normally  on  each  whig-cover,  seven  on  thorax  with  two  fainter 
ones  on  front  margin,  while  the  eyes  look  like  two  black  spots  on 
the  head.  These  lady-birds  are  California  forms,  and  have  not  be- 
fore been  reported  from  New  Mexico. 

To  the  true  dipterous  parasites  belongs  the  Lesfophonus 
icerijfu\  which  was  found  parasitic  on  leery  a  in  Australia,  and  was 
imported  under  Professor  Eiley's  direction  into  California.  It  has, 
however,  been  superseded  in  usefulness  by  the  Vedalia,  and  some 
other  coccinellid  beetles  which  were  imported  later. 

REMEDIES    FOR    SCALE-INSECTS. 

Summer  Washes. — As  a  summer  wash  for  the  San  Jose  scale, 
and  other  species  of  Aspidiotus  infesting  deciduous  trees,  the  fol- 
lowing should  be  applied  at  various  times  after  the  young  scales 
have  hatched  and  are  seen  crawling  on  the  bark : 

No.  1.      Caustic  soda  (98  per  cent.)  .  .  10  Ibs. 

Potash 10  Ibs. 

Tallow 40  Ibs. 

Eesin  .  . . 40  Ibs. 

Water  to  make 50  gals. 

The  above  forms  a  soap  which  will  fill  a  barrel  of  50  gallons 
measure,  and  will  weigh  about  450  to  500  pounds.  It  must  be 
prepared  as  follows: 

First,  dissolve  the  soda  and  potash  in  ten  gallons  of  water, 
then  place  the  whole  in  a  50-gallon  barrel.  Second,  dissolve  the 
tallow  and  resin  together  by  heating  it  over  a  fire,  add  it  to  the 
soda  and  potash  in  the  barrel,  and  stir  well  for  about  five  minutes. 
Let  it  stand  now  for  about  two  hours,  when  the  barrel  may  be  filled 
up  with  water,  but  the  mixture  must  be  well  stirred  as  every  bucket 
of  water  is  added.  It  will  be  ready  for  use  the  following  day,  and 
should  be  applied  warm  in  strength  of  one  pound  of  soap  to  a  gallon 
of  water.  This  remedy  is  preferable  for  apples  and  pears,  and  was 
originally  recommended,  I  believe,  by  Mr.  Sol.  Runyon,  of  Court- 
land,  Cal. 


IS  SCALE-INSECTS 


The  following  is  recommended  in  California  for  same  purpose, 
but  for  use  on  the  peach: 

No.     2.      Potash 14  Ibs. 

Caustic  soda  (98  percent.) ....  8  Ibs. 

Unslacked  lime 5  Ibs. 

Fish  oil,  polar  or  seal 10  gals. 

Water  to  make 50  gals. 

Prepare  as  follows:  First,  dissolve  thevsoda  and  potash  in  ten 
gallons  of  water,  as  with  the  preceding  formula.  Then  slack  the 
lime  with  two  gallons  of  water  in  the  50-gallon  barrel  to  be  used, 
add  the  fish  oil  and  stir  well  until  the  lime  and  oil  form  a  thick 
batter.  Now  pour  the  soda  and  potash  solution,  boiling  hot,  into 
the  barrel  containing  the  batter,  and  stir  well  with  a  dasher  for  five 
minutes.  Leave  standing  from  4  to  6  hours;  after  this  length  of 
time  the  barrel  may  be  filled  up  with  cold  water,  about  two  buckets 
full  at  a  time,  stirring  well  to  prevent  lumps.  Use  the  following 
day  and  apply  cold,  in  strength  of  one  pound  to  a  gallon  of 
water. 

In  dissolving  this  soap  for  use  do  not  boil,  but  weigh  amount 
to  be  used,  place  in  barrel  and  pour  hot  water  thereon,  in  propor- 
tion of  one  pailful  to  every  one  hundred  pounds  of  material ;  then 
stir  briskly  with  a  dasher  until  entirely  dissolved.  It  can  now  be 
reduced  with  cold  water  as  above  directed,  making  as  many  gallons 
of  wash  as  there  were  pounds  of  soap  dissolved.  After  being  well 
stirred,  it  is  ready  for  use.  This  wash  is  also  recommended  in  Cali- 
fornia for  leery  a  on  citrus  trees  and  evergreens,  and  for  Lccanhunx 
on  deciduous  or  other  trees. 

Another  summer  resin  wash,  recommended  by  Professor  Riley 
for  the  red  scale  on  the  orange  in  California,  differs  from  the  above 
washes  by  containing  no  potash,  and  proportionally  more  than 
twice  as  much  resin.  It  will  doubtless  be  efficient  for  all  species  of 
Aspidioius,  except  the  San  Jose  scale,  but  if  used  on  deciduous 
trees  it  should  be  experimented  with  first  to  determine  effect  011 
the  foliage.  If  the  foliage  is  injured,  more  water  can  be  added. 
The  formula  is  as  follows: 


IN  NEW  MEXICO. 


No.     3.     Eesin 18  Ibs. 

Caustic  soda  (70  per  cent.).  .  .      5  Ibs. 

Fish  oil < 2J  pints. 

Water  to  make 100  gals. 

It  also  differs  from  the  preceding  resin  washes  in  the  manner 
of  preparation,  and  in  being  ready  for  application  when  mixed  ac- 
cording to  the  above  formula,  instead  of  forming  a  soap  to  be  dis- 
solved again  in  water.  It  is  prepared  as  follows: 

Place  all  the  ingredients  in  a  large  boiler  with  enough  cold 
water  to  cover  them.  Boil  until  dissolved,  occasionally  'stirring, 
and  continue  boiling  for  about  an  hour  after  the  materials  are  dis- 
solved, employing  sufficient  heat  to  keep  the  mixture  in  a  constant 
state  of  ebullition,  and  adding  hot  water  when  it  is  in  danger  of  boil- 
ing over.  When  sufficiently  boiled  it  will  assimilate  perfectly 
with  water,  which  should  then  be  added  hot  up  to  50  gallons,  slowly  at 
first  and  stirring  occasionally,  and  then  cold  water  until  a  sufficient 
amount  is  added  to  make  100  gallons  of  the  mixture.  Before  the 
water  is  added  the  preparation  is  of  a  pale  yellow  color,  but  after 
a  adding  it  becomes  dark  brown.  It  must  be  strained  through  a 
fine  wire  seive,  or  a  piece  of  Swiss  muslin,  before  applying  to  the 
trees. 

Virtually  the  same  remedy  as  the  above,  only  in  a  little 
greater  strength  and  with  the  addition  of  a  little  kerosene,  is  re- 
commended by  the  Calif oraia  State  Board  of  Horticulture  for  the  red 
scale  on  orange,  and  other  scales  on  evergreen  trees ;  while  the  same 
thing,  only  a  little  stronger  and  without  the  kerosene,  is  recom- 
mended for  Icc-r'ijfi  on  the  orange. 

The  following  is  the  Riley-Hubbard  formula  for  the  kerosene 
emulsion,  which  at  proper  strength  will  be  found  a  very  efficient 
remedy  for  scales: 

No.     4.      Kerosene  oil 2  gals. 

Common  soap ^  11). 

Water .  .  1  gals. 

o 

Prepare  by  boiling  the  water  and  soap  together  until  dissolved, 
and  then  pouring  it,  while  boiling  hot,  into  the  kerosene.  The 


SCALE-INSECTS. 


mixture  must  now  be  pumped  through  a  force  pump  for  about  five 
minutes,  directing  the  stream  back  into  the  pail,  until  it  forms  a 
perfect  emulsion.  As  a  summer  wash  for  San  Jose  and  other 
scales  on  apple,  pear,  etc.,  dilute  nine  times  with  cold  water.  For 
use  on  peach,  dilute  fifteen  times. 

The  following  summer  wash  for  San  Jose  scale  on  deciduous 
trees  is  recommended  by  the  California  State  Board  of  Horti- 
culture : 

No.  .5.     Whale  oil  soap  (80  per  cent.).    20  Ibs. 

Sulphur 3  Ibs. 

Caustic  soda  (98  per  cent.) ....      1  Ib. 

Commercial  potash 1  Ib. 

Water  to  make 100  Ibs. 

Boil  the  sulphur,  soda  and  potash  in  two  gallons  of  water  for 
one  hour,  or  until  thoroughly  dissolved.  Dissolve  the  soap  by 
boiling  it  in  water,  then  add  to  the  other,  mix  and  boil  for  a  short 
time  when  it  may  be  applied  hot. 

Winter  Washes. — In  order  to  thoroughly  destroy  the  San 
Jose  scale,  it  will  be  necessary  to  use  the  following  winter  wash, 
which  is  much  stronger  than  any  of  the  preceding  and  must  be  ap- 
plied only  when  the  tree  is  dormant.  If  applied  in  the  growing 
season,  it  will  cause  the  loss  of  both  foliage  and  fruit.  It  is  recom- 
mended by  Professor  Riley  as  giving  the  best  results  of  all  for  use 
as  a  winter  wash  against  this  particular  scale.  It  therefore  needs- 
no  further  commendation : 

No.     0.     Kesiii 30  Ibs. 

Caustic   soda  (70  per  cent.).  .  .      1)  Ibs. 

Fish  oil 44  pints. 

Water  to  make 100  gals. 

Prepare  by  placing  all  the  ingredients  in  a  large  boiler,  and 
pouring  over  them  about  20  gallons  of  water.  Boil  briskly  for 
three  hours,  or  until  the  compound  is  perfectly  soluble  in  water.  The 
boiler  must  now  be  slowly  filled  up  with  hot  water,  care  being  taken 
to  stir  well,  until  it  makes  50  gallons  of  hot  solution.  This  should 


NEW    MEXICO.  21 


be  strained  through  a  fine  wire  seive  or  a  piece  of  muslin,  when  it  can 
be  diluted  with  an  equal  quantity  of  cold  water  as  needed  for  spray- 
ing. It  is  recommended  in  California  for  Lecaniums,  as  well  as 
San  Jose  scale,  for  winter  use  on  deciduous  trees. 

In  the  application  of  this  wash  a  very  fine  spray  is  not  essen- 
tial, as  the  object  to  be  attained,  that  of  thoroughly  coating  the 
tree  with  the  compound,  can  be  best  accomplished  by  the  use 
of  a  rather  coarse  spray,  to  be  thrown  on  the  tree  with  consid- 
erable force. 

The  California  State  Board  of  Horticulture  recommend  the 
following  as  a  winter  wash  against  the  San  Jose  and  congeneric 
scales.  It  is  claimed,  and  I  believe  with  reason,  that  the  addition 
of  potash  to  the  wash  is  necessary  to  prevent  the  dry  atmosphere 
from  exhausting  the  caustic  properties  of  the  soda.  This  is  espec- 
ially important  to  us  in  New  Mexico,  as  our  atmosphere  is  much 
dryer  than  that  of  of  California.  If  soda  lye  alone  is  sprayed  on 
trees  in  sunny  weather,  it  will  often  be  found  within  an  hour  to  have 
crystallized  into  solid  carbonate  of  soda,  and  its  action,  so  far  as  in- 
sects are  concered,  is  at  an  end.  If  sprayed  in  moist  weather,  its 
action  is  prolonged.  The  addition  of  the  potash,  however,  main- 
tains the  corrosive  action  of  the  soda  in  the  dryest  atmosphere,  by 
preventing  the  rapid  evaporation  and  solidification  which  would 
otherwise  put  an  end  to  it.  Besides  the  potash  ultimately  reaches 
the  soil,  and  acts  as  a  fertilizer  when  needed.  The  above  statements 
are  on  the  authority  of  Professor  Hilgard. 

No.  7.      Solid  concentrated  American  lye  (80  per  cent.).  .    1  lb.,    or 

Powdered  caustic  soda   (98  per  cent.) 0.8  lb.,  or 

Powdered  caustic  soda  (76  per  cent.) 1  lb.,    or 

Powdered  caustic  soda  (63  per   cent.) 1£  Ibs.,  to 

Commercial  potash  (52  per  cent.) 1  lb.,  and 

Water 2|  gals. 

Simply  dissolve  the  soda  and  potash  in  the  water.  First  re- 
commended by  Mr.  M.  Cooke. 

The  following  formula,  recommended  by  Professor  Hilgard,  is 


22  SCALE -INSECTS 

undoubtedly  equally  as  good  as  the  last,  and  costs  one  cent   less  per 
gallon. 

No.  8.     Solid  concentrated  American  lye  (80  per  cent.)  .  .  1  lb.,  or 
any  one  of  the  sodas  in  preceding  formula,  to 

Commercial  potash  (52  per  cent. )    i  lb. 

Water    2    gals. 

Simply  dissolve.  This  is  just  a  little  more  than  one  half  the 
strength  of  potash  that  is  given  in  the  preceding  formula. 

Comments. — The  above  8  washes  are  given  so  as  to  allow  some 
latitude  in  choice.  They  have  been  carefully  selected,  and  will 
doubtless  all  prove  more  or  less  efficient.  Those  which  will  be  of 
use  for  species  of  Aspidiotus  and  L&canium,  are  mentioned  above. 
The  last  two  formulas  mentioned  would,  I  believe,  be  especially  ad- 
apted to  our  climate. 

For  Lecanodiaspis,  or  other  scales  on  Dasylirion  and  Yucca,  I 
would  recommend  formula  No.  6,  to  be  applied  at  any  time  of  the 
year.  No.  4  diluted  five  times  would  also  be  of  service,  and  would 
in  all  probability  not  affect  the  plants. 

As  far  as  the  scale  on  Larrea  goes,  it  will  probably  not  spread 
to  any  other  plant,  and  doubtless  the  creosote  bush  is  not  valuable 
enough  here  to  call  for  any  protection.  However,  No.  P>  and  No.  4, 
as  above  recommended,  would  be  the  proper  remedies. 

For  species  of  Icerya,  and  for  cottony  scale  on  mesquite,  No.  3  is 
the  formula  which  should  be  used,  but  the  caution  given  above  as  to 
trying  the  wash  first  to  get  the  strength  which  will  not  injure  such 
foliage  as  grape  or  mesquite,  must  be  heeded. 

No  mention  is  made  in  this  bulletin  of  the  hydrocyanic  acid 
gas  method  of  destroying  scale-insects,  which  is  at  the  present  time 
unnecessary  in  this  territory. 

EXPLANATION    OF    PLATES. 

Plate    I. 

(  All  much  enlarged.  ) 

Fig.  1. — San  Jose  scale,  Aspidiotus  pprniciosits.  last  abdominal  segment   of  female 
showing  specific  characters. 


IN    NEW    MEXICO. 


Fig.  2. — White  pear  scale.  Aspidiotus  rapax,  last  abdominal  segment  of  female  show- 
ing same. 

Fig.  3. — Convex  scale,  Aspidiotus  convexus,  last  abdominal  segment  of  female  show- 
ing same. 

Fig.  4. — San  Jose  scale  parasite,  Aphelinus  mytilaspidis. 

Plate  II. 

Palmer's  Icerya,  leery  a  palmeri. 
Fig.  1. — a,  newly  hatched  larva;  6,    larva,  second  stage    (both  greatly    enlarged — 

hairlines  indicate  natural  size);  c,  antenna  of  6  (still  more  enlarged). 
Fig.  2. — a,  cast  skins  of  larvae  of   second  stage  (much  enlarged) ;   6,  s  ame  clustered 
on  ribs  of  grape  leaf,  on  underside  (natural  size). 

Plate    III. 

This  plate  shows  a  spraying  outfit  in  operation,  as  used  in  orange  groves  in 
California  against  the  fluted  scale. 

NOTE. — The  above  plates  were  all  received  from  the  Agricultural  Department  in 
Washington,  and  appeared  either  in  Insect  Life  or  in  the  reports  of  the  U.  S. 
Entomologist. 


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